NOCOMMIT: Blink tracing now uses base

third_party/WebKit/Source/platform/TracedValue.h

Index: third_party/WebKit/Source/platform/TracedValue.h
diff --git a/third_party/WebKit/Source/platform/TracedValue.h b/third_party/WebKit/Source/platform/TracedValue.h
index 79b877bc4e654c0d378ecba1c6c8a6c2498c0526..05b1b7eb42a7cc074566d93100d161348efa9f50 100644
--- a/third_party/WebKit/Source/platform/TracedValue.h
+++ b/third_party/WebKit/Source/platform/TracedValue.h
@@ -5,7 +5,10 @@
 #ifndef TracedValue_h
 #define TracedValue_h
 
+#include "base/trace_event/trace_event.h"
+
 #include "platform/EventTracer.h"
+#include "platform/PlatformExport.h"
 
 #include "wtf/PassRefPtr.h"
 #include "wtf/text/WTFString.h"
@@ -19,11 +22,11 @@ class InternalValue;
 typedef Vector<RefPtr<InternalValue>> TracedValueVector;
 typedef HashMap<String, RefPtr<InternalValue>> TracedValueHashMap;
 
-class PLATFORM_EXPORT TracedValue : public TraceEvent::ConvertableToTraceFormat {
+class PLATFORM_EXPORT TracedValue : public base::trace_event::ConvertableToTraceFormat {
     WTF_MAKE_NONCOPYABLE(TracedValue);
 
 public:
-    static PassRefPtr<TracedValue> create();
+    static scoped_refptr<TracedValue> create();
 
     void endDictionary();
     void endArray();
@@ -42,7 +45,7 @@ public:
     void beginArray();
     void beginDictionary();
 
-    String asTraceFormat() const override;
+    void AppendAsTraceFormat(std::string* out) const override;
 
 private:
     TracedValue();